US2583736A - Gas heater - Google Patents

Description

F. O. HESS GAS HEATER Jan. 29, 1952 Filed Feb. 25, 1946 Puentes Jee. zo, 1952 Setas Corporation of America,

Philadelphia,-

Pa., a corporation of Pennsylvania Applicationlfehruary 23,l 1946, Serial No. .849,675

s onine.. (ci. zen-1s) My invention relates te the art or producing a high velocity gas stream of heated products of combustion in which another medium is mixed therewith, and, although not to be limited there to, is especially concerned withthe production of 'such a high velocity gas stream whose temperature may be accurately controlled by mixing therewith regulated quantities of another gaseous medium at a temperature less than the temperature of the products of combustion.

In accordance with the invention, heated prod# ucts of combustion` are maintained in a.l rst space at a pressure appreclably above that of atmospheric and discharged therefrom through a restricted outlet, and a medium at a temperae less than the temperature of the products o combustion is supplied to a second space which envelops at least the outlet end of the nrst space, such medium being discharged from the second space through a discharge port and commingling with the heated products of combustion in a high velocity gas stream. e "i A gaseous medium, such as air, nitrogen or carbon dioxide, for example. is supplied to the second space which mixes with the heated products of combustion discharged from the iirst space, and such mixture thendischarged in the form of a high velocity gas stream from the discharge port of the second space. Byrontrolling the supply of the gaseous medium to the f second space and the rate at which the latter mixes with 4the heated products of combustion, the temperature of the heated gas stream pro- 2 combustible gaseous mixture a suitable source of supply.

The inlet chambers Il at each side of the central inlet chamber I2 are provided with threaded inlets I1 which receive conduits I8 through which is delivered from a gaseous 'medium is delivered, as will be ex-v plained more fully hereinafter. In one of the conduits Il is provided a manually operable valve Il for controlling the rate at which the gaseous medium is supplied to the burner I0. It is to be y understood that a similar manually operable duced at the discharge port of the second space can be nicely regulated through a wide temperature range from a low temperature to the temperature of the heated tion.

The invention, together with the objects and advantages thereof, will be more fully understood upon reference to the following description and accompanying drawing forming a part o! products of combus- -this specification, and of which Fig. 1 is a vertical plan view of a gas burner embodying the invention; Fig. 2 is a. vertical sectional view, taken on line 2--2 of Fig. 3, to illustrate the burner more clearly; and Fig. 3 is a horizontal sectional view, taken on line l-l 0f llig.l 2, to illustrate details of the burner. l y

Referring ,to the drawing, the gas-burner Il embodying the invention includesa base member Il shaped to form a pluralityo! inlet chamvalve may be provided in the other conduit Il. The base member Il is formed with internal shoulders 2l at' the upper part of the inlet cham-- ber I2 to receive an apertured member or burner screen 2| formed with a plurality of openings or passages 22. As shown most clearly in Fig. 3, the burner screen 2| comprises a plurality of relatively thin plates stacked and closely held together. One face of each plate is formed with a plurality of slots of relatively small depth. and the plates are stacked together with a slotted face of each plate, except one end plate, contiguous to and contacting a smooth face of an adjacent plate. Although not to be limited thereto, the thin plates forming the burner screen 2| may be formed of suitable refractory material.

To the top surface of the base member II is secured a slotted clamping plate 23, as by screws 24, `for example, which overlles ilanges or lugs 2l formed at opposing sides of the burner screen 2|. The clamping plate 23 is also formed with two rows of openings 26 each of which is directly above the top reduced portions of the inlet chambers Il. In order-,to obtain a gas-tight seal. about the burner screen 2| and the openings", argasket 2,1 formed of suitable materil,

. such=as asbestos, for example, is interposed vbebers I2 and Il. The centrally disposed inlet chamber I2 is provided with a threaded inlet Il which receives a conduit It through which a sa form to tween the plate 22 and the base member I I. The spaces 28 above the lugs 25 may be filled with a suitable high temperature nre-brick cement.

The large open end of a cup-shaped metal shell or casing 28 is removably secured at 30 to the-,base member II. Within the outer shell 29 is provided an outer wall or lining of refractory material. The outer refractory lining is formed by a hollow rectangular shell comprising two complementary wall parts, U-shaped in horisontal section, and having parallel ends II. 'I'he extreme vertical Z-shaped edges of opposing ends 2| at each end of the burner I0 are in abutting relatiomas indicated at 32 in- Fig. 3.

As best shown in Fig. 2, the outer surtacesfof the sides I2 of the outer refractory lining conthe shape of the metal shell 2l. --The ends 3| of .the outer refractory wail parte are straight throughout the heights ofv these walls while the connecting side w'alls 32 include straight -wall portionsextending upwardly fromthe clamping plate 23 to an intermediate part of the outer refractory lining, and inwardly sloping. wall portions which terminate in a narrow rectangular-shaped slot ordischarge port 33a extending or projecting through an opening at the top part of the metal shellA 28.

A second inner refractory lining is disposed within theY outer refractory lining just described and forms'a combustion chamber 34. The inner refractory lining is also formed by a hollow rectangular shell comprising two complementary parts, U-shaped'in horizontal section,\and havignited to produce and maintain a name at the discharge port 33.

When a flame is being maintained atthe discharge port 33 the pressure of the gaseous mixture supplied to the burner 0 is then reduced suiliciently to cause the flame to backfire'from the discharge port 33 onto the burner screen 2| in chamber 34. When this occurs aplurality of ilames are produced and maintained at the upper ends of the openings 22.

When the flames are being maintained within chamber V34 at the top surface of the burner screen 2|, thepressuregofthe gaseous mixture supplied to the burner I0 may be increased.

ing parallel ends 35 over which snugly t the ends 3| of the outer refractory wallparts. The

.extreme vertical Z-shaped edges of opposing ends 35 at each end of the burner I0 are in abutting relation, as indicated at 36 in-Fig. 3.

After a short interval of time, the flames main# tained atthe top surface of the burner screen 2| effect such heating' of the inner refractory lining that these surfaces are heated to a highly incaning overlie and Vilt snugly against the peripheral edges of the narrow portion of the apertured member or burner screen 2| extending through the slot in clamping plate 23 toward the outlet 38. The side walls 31 of the inner refractory lining are rigidly held in position against the upper part of the burner screenv 2| by vertically extending ribs 33 formed at the inner surface of the side walls 32 of the outer-.refractory wall parts.

The ribs 33 extend vertically upward from the clamping plate 23 toa region adjacent to the outlet 38 formed by the inner refractory lining. and spaces 48 betweenadiacent spaced apart ribs- 33 form vertically extending passages which communicate at their lower ends with the openings 26 in the clamping plate 23. When the cupshaped shell 23 is'secured to the base member at 38. both the outer and inner refractory linings are rigidly held in position, the bottom parts of the ribs 39 bearing against the inner refractoryV lining to cause thelatter to nt snugly against the upper narrow part of the burner .screen 2| while the top sloping parts of the ribs exert a downward component of force against the upper part of the inner refractory lining so that the latter will beiirmly held and seated against clamping` plate 23.

When it is desired to employ the burner ||I to produce a high velocity gas stream of heated products of combustion, a combustible fuel mixture comprising a' gaseous fuel and a combustion supporting gas is supplied through conduit I6 from asitable source of supply. When the burner I8 is relatively cool and at the ambient temperature, the gaseous mixture supplied thereto passes through the inlet chamber |2, burner screen 2|, and chamber 34 from which it is successively discharged through the outlet 38 and discharge port 33. The combustible gaseous mixture is initially supplied to the burner I8 at a relatively low pressure which may be equivalent to 5 or 6 inches of water column. for example, so that the gaseous mixture discharged from the chamber 34 4can be descent condition, Due to heating of the inner refractory lining topa high temperature, substantially complete combustion of the gaseous mixture ,is accomplished in chamber 34 before the mixture reaches the restricted outlet 38. From the outlet 38 is discharged a high velocity jet or stream of heated gases consisting substantially entirely of the heated products of combustion.

During normal operation the burner is characterized by the absence of a bright and luminous flame. It is only when the burner I0 is' first started that a flame is momentarily maintained at thev elongated slot ordischarge port 33, as previously explained. After the gaseous mixture has once been ignited, the delivery pressure of the gaseous mixture is reduced suiciently to cause backfiring into the chamber 34, so that burning `of the gaseous mixture will take place at the top surface of the burner screen 2|.

In a burner of the type just described, the heated products of combustion are discharged from the combustion chamber 34 through the restricted outlet 38 thereof at an elevated temperature ranging from 2700 F. to 2900 F. and higher when a combustible-gaseous mixture of air and ordinary gas, such as city gas, for example,

is supplied at a pressure in the neighborhood of l three pounds per square inch. Undersuch operating conditions, the pressure in the combustion chamber 34 may be equivalent to from 55 to inches of water column and appreciably above that of atmosphericpressure.

The gas stream discharged from the combustion chamber 34 through its outlet 38 is at a temperature nearly equal to `the temperature in the combustion chamber. In many instances it is desirable to produce such a highv velocity gas stream which is' at a temperature below that prevailing in the combustion chamber 34. In accordance with the present invention, this is accomplished in the burner I0 by providing the passages 40 at each side of the central chamber 34 which communicate with the inlet chambers I4 and to which a suitable medium may be supplied through the conduits |8.

In a burner of the character described, a suitable gaseous medium, such as air,nitrogen or carbon dioxide, for example, may be supplied through the conduits I8 to the inlet chambers I4 for flow through the passages 40. Such gaseous medium supplied to the passages 40 mixes with the heated products of combustion emerging through the restricted outlet 38, and such mixture then issues from the burner l0 at the discharge port 33 at a temperature depending upon. the supply of the gaseous medium to the passages 40 and the rate at which the gaseous mixture mixes with the heated products of com- 1 bustion. i

'I'he gaseous medium maybe positively fed under pressure through the conduits il for ii'ow valves connected inthe conduits Il, only one end of each is shown at i9, can be eifectively employed to control the rate of flow of the gaseous medium through the passages 4I, whereby the temperature of the heated gas stream produced at the discharge port 3l can be nicelyA regulated through a wide temperature range l e@ We' sels en im *it* oneend and restricted outlet at its opposite end,

' said structure-providing said other spaces being formed and shaped so that the latter merge at the outlet end of said central 'space to form a region enveloping. said outlet which is provided with a discharge port substantially in alignment with said outlet, said 4inlet for said central space having a number of small passages for subdividing into a plurality of gas streams a combustible gaseous mixture adapted to be supplied from a low temperature to the temperature of the heated products of combustion issuing from the combustion chamber 34.

When it is desired to-produce a stream of heated gases at the discharge port 33 whichv is at the highest possible velocity, the gaseous medium under such conditions is preferably supplied under pressure `through the conduits i! to the passages 40. In certain instances it may be desirable to inspirate thev gaseous medium into the passages 40. as just explained. and under such conditions the velocity of the heated products oi.' combustion discharged through the restricted outlet 38 is reduced depending upon the extent to which the gaseous medium is entrained in the heated products of combustion.

It will now be understood that the passages Il form a plurality of spaces at each side of the combustion chamber 34 which are separated therefrom by a partition formed by the inner refractory lining. 'I'he outer refractory lining, which provides the spaces at each side of the combustion chamber 3l, is formed and shaped to provide a slotted region enveloping the restricted outlet 38. Hence, the outer refractory lining having the elongated slot or discharge port Il forms a hood enveloping at least the outlet end of the combustion space 3l to provide a path of flow in which a medium at a temperature less than the temperature of the products of combustion is supplied, such medium being discharged through the port 33a and commingling with the heated products of combustion in a high velocity gas stream. The wall parts forming the inner` and outer linings of the burner i0 may be formed of a suitable high temperature refractory material, such as mullite, for example.

Although a single embodiment of the invention has been shown and described, it will be obvious to those skilled in the art that various changea and modifications may be made in practicing theinvention. Thus, the relative positions of the restricted outlet 38 and discharge port Il with respect to each other may vary depending upon the character of the heated gas stream desired to be produced by the burner l0` and the manner and extent to which the medium, which is at a lower temperature than the heated products of combustion, comingles with the latter in the resulting gas stream produced. I thereforeaim in the following claims to cover all changes and modifications which fall within the true spirit and scope of the invention.

What is claimed is: 1. A burner comprising structure including a partitioned hollow body which provides a plurality of individual spaces alongside of each other separated by partitions, one of said spaces being centrally disposed between two other thereto under pressure, .said central space having its outlet and inner wall surface formed of high-,temperature refractory material so that combustion of the gas streams may be effected within said space and cause heating of the inner wall surface thereof to incandescence :and proy duce a region of intense heat in which substantially complete combustion is accomplished while products of combustion are discharged from said lcentral space through said outlet at atemperature nearly equal to the temperature in said space, and said other spaces having inlets for a gaseous medium adapted to be supplied thereto at a temperature less than the temperature of the products of combustion, whereby such gaseous medium is discharged from said other spaces through said discharge port and merges with the heated productsV of combustion to form a gas stream.

2. In a gas burner the ,combination of structure forming a combustion chamber having a restricted outlet and an inlet, a screen provided with a plurality of small passages across said inlet, means through which a combustible mixture is forced through said screen to burn in said chamber, the products of combustion issuing at high velocity through said outlet, structure forming additional chambers on opposite sides of said combustion chamber, said additional chambers extending beyond said combustion chamber and having a common restricted discharge port axially aligned. with said outlet, and

'means through which a iluid can be forced into said additional chambers to be mixed with the products of combustion between said outlet and said discharge port.

3. A gas burner including structure forming a combustion chamber having a restricted outlet, additional structure' forming an additional chamber substantially surrounding said combustion chamber and having a restricted discharge opening axially aligned with said outlet and beyond the same, a base member having compartments therein upon which said structure is mounted, a compartment communicating with each of said chambers, a screen located between said combustion chamber and the compartment communicating therewith, means to supply a combustible mixture to the last-mentioned compartment to be burned in said combustion chamber and issue through said restricted outlet as hot products of combustion, and means to supply a gas to the remaining compartments to pass through said additional chamber and 'mix with the products of combustion as they pass beyond said outlet and through said discharge opening.

4. A gas burner including a base member having a plurality of compartments therein, a screen formed with a plurality of passages therein over one of said compartments, a plurality of ceramic I parts cooperating to form a combustion chamber .parts surrounding said first-mentioned ports and forming a pair of chambers on opposite sides o f said combustion chamber and extending beyond the same, said additional parts extending to form a common discharge opening for said additional chambers aligned with said outlet, means to attach said additional parts-to said member with said pair of chambers each over a compartment in said member, means through which a comforced through said member and into said additional chambers.

FREDERIC O. HESS. l5 2,225,775

REFERENCES CITED The following references are of record inthe le of this patent:

UNITED STATES PATENTS Number Name l Date 1,311,235 Kemp et al. July 29, 1919 1,863,391 Bluemel June 19, 1932 1,991,750 Keeling Feb. 19, 1935 '2,044,715 Bluemel June 16, 1936 2,107,365 Bray Feb. 8, 1938 2,147,925 Schwalbe Feb. 21, 1939 2,174,962 Blayney Oct. 3, 1939 `Garrett Dec. 24, 1940

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